A complete 5 KV motor circuit includes power components relating the 5K volt rack mounted power cell and low voltage control protective relaying which include a ground fault relay, ground wire monitor, short circuit and overload relays. The prior art 5 KV pull out cells use a single draw out assembly consisting of both power and control components. As a result, when one of the power or the control components fails, both of the components are required to be replaced at an added expense.
U.S. Pat. No. 7,277,294 describes a contactor draw out tray that has a movable frame and a stationary frame which carries the electrical components for an electrical feeder circuit and has input terminals for the incoming electrical power and output terminals for delivering electrical power to equipment operating on the feeder circuit. The movable frame carries the contactors. A disconnect mechanism locks the movable frame relative the stationary frame and provides a primary mechanical means for disengaging electrical current flow through the apparatus. While the contactor draw out tray provides access for repairs, the operator is required to stand in front of the device to mechanically disengage the electrical current flowing between the input and output terminal before the tray can be drawn out for repairs.
An earlier draw out fused switch gear assembly is taught in U.S. Pat. No. 3,274,356. The assembly is adapted to be removably engageable with fixed electrical connectors from a electrical source. Another early patent, U.S. Pat. No. 2,982,827, describes an interlocking mechanism for use with a slidably mounted electrical draw out unit for forward and backward movement between an advanced and a retracted position in which movable contacts of the high voltage supply source that mate with stationary source.
Other prior art patents include U.S. Pat. No. 6,169,653 issued Jan. 2, 2001 which teaches a latch and locate cradle; U.S. Pat. No. 6,127,742 issued Oct. 3, 2000 describes a draw-out electrical switchgear apparatus; U.S. Pat. No. 6,031,192 issued Feb. 29, 2000 describes a draw out circuit breaker with disconnect position interlock mechanism; U.S. Pat. No. 4,482,936; U.S. Pat. No. 3,896,353; U.S. Pat. No. 3,716,684; and U.S. Pat. No. 2,554,510.
To solve the problems associated with the prior art draw out cells, the methods, systems and apparatus of the present invention separate the power components which seldom need to be replaced from the protective relaying control components which have a much higher failure rate.